In the past there have been many forms of solar heat exchangers. There have been serpentine and manifold heat exchangers as is illustrated by U.S. Pat. Nos. 4,059,095 and 4,120,286 respectively. There have been solar heat exchangers which attempted insulation at the top of the structure by means of an insulation layer such as those represented by Stout, U.S. Pat. No. 3,918,430 wherein solar energy was trapped by the panels located at the top of the structure. There have even been attempts at insulation at the bottom such as the Stout structure. These structures have been found lacking in that the structures fail to raise the fluid temperatures to a high enough level which would be more desirable by a user.
Applicant has provided a structure wherein there is a frame having an inner surface within the frame having insulation material uniformly spread throughout it, the channels are provided throughout the inner surface resting upon and surrounded by the insulation, the channels comprise an outer and an inner wall restricting the flow of fluid through the channels to a thin film which may be heated to a temperature higher than would ordinarily be possible with the structures described above.
Applicant has invented a structure wherein the sun's solar energy is transformed into a heating source which may be used, for example, in pools, bathing water and in general as a convenient, economical heat source as well as industrial use.